Below are some answers to commonly-asked questions about GPS in general and how GPS can help EMAGIN®.
What is GPS?
GPS stands for Global Positioning System. It is U.S. owned and is one of a number of Global Navigation Satillite Systems (GNSS). Other global satilite systems currently in use or development are GLONASS (Russia), Galileo (EU and partner countries, planned to be operational by 2014) and COMPASS (China, planned to be operational by 2020).
A GPS has three components:
Satellites that orbit the Earth
Monitoring and Control Stations on Earth
The Reciever
How does it work?
The 24 satellites transmit one way radio signals at set times. A GPS reciever detects a signal and references an almanac to work out the time of the signal origin and the position of the satelite. It then uses a simple formula (Distance = speed of signal x signal travel time) to calculate the distance to the satelite. A minumum of four satellite signals are needed to give an accurate position as the GPS reciever triangulates from these distances to work out its three dimensional position (latitude, longitude and altitude) and time.
How accurate are they?
As mentioned, at least four satellite signals are required for effective triangulaton but a number of things can impede transmission including thick tree canopy, nearby tall buildings and some atmospheric conditions. Additionally, different GPS recievers have different levels of accuracy. Most recreational recievers have a accuracy level of up to 10 metres but newer top end units will improve on this. But 10m could mean the difference between riding down one side of a hedgeline or the other so for the purposes of EMAGIN, all routes need to be verified by the Mapping Volunteer before sending in the GPS files.
How does GPS benefit EMAGIN?
GPS greatly speeds up the process of data collection for EMAGIN® because it is the most efficient and publicly accessible technology available. It also moves equestrian mapping and access into the digital era and it ensures that the BHS are at the forefront in digitising equestrian information.
I have a GPS and will be using that to record rides locally : how can I send you my data?
Record a track log of the ride, and any points of interest along the way (e.g. start position, car parking). Send the track and waypoint data in separate files, with a ‘trk’and ‘wpt’file name suffix respectively. We can process all the standard proprietary GPS data formats but the preferred format is GPS Interchange (‘gpx’).
I would like to buy a GPS unit : do you have any recommendations?
We do not endorse any particular make or model of GPS and there are no units aimed specifically for horse riders. High Street outdoor and leisure retailers stock a small range of the available models and should be able to provide advice, and a demonstration of the features.
Can I submit my ride as a Google Maps link?
It depends on how the ride was mapped. If the ride was recorded on an iPhone or other smartphone, it can be uploaded to the web and a link (URL) provided. The URL can then be used to access the data and generate a ‘kml’ file for further use. If the ride was traced manually using Google Maps this would not be suitable as the base map does not show bridleways and other rights of way; also as the data was “derived” from Google Maps there could be issues around data ownership.